Fire-alarm system for telephone-exchanges using line-distributers.



DAVID G. DEE, OF ROCHESTER, NEW YORK, ASSIGNOB, BY MESNE ASSIGNMENTS, TO ROCHESTER H. ROGERS, OF ROCHESTER, NEW YORK.

FIRE-ALARM SYSTEM FOR TELEPHONE-EXCHANGES USING LINE-DISTRIBUTERS.

Specification of Letters Patent.

Patented July in, 1917.

Application filed February 25, 1914. Serial No. 820,951.

To all whom it may concern Be it known that I, DAVID G. DEE, of

Rochester, in the county of Monroe and exact description of the same, reference be-- ing had to the accompanying drawings, forming a part of this specification, and to the reference-numerals marked thereon.

My present invention has for its object to provide a fire alarm call box and a circuit system to be used in conjunction therewith for the transmitting of fire alarm signals over subscribers" telephone lines which are part of, or operate in conjunction with, the so called semi-automatic, auto-manual and any other system in which in-coming calls on a plurality of subscribers circuits are distributed by automatic switches to an idle trunk of a group of trunk circuits. Tothese and other ends the invention consists in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specification.

In the drawings:

The figure is a diagrammatic illustration showing mechanism illustrating one embodiment of my present invention.

My present invention has for its object to extend the usefulness and render practical the use of fire alarm signal boxes which despatch code signals when such boxes are ap plied to semi-automatic, auto-manual or other telephone systems in which the calls initiated in a group of subscribers circuits are distributed over a smaller number of trunk circuits. This distribution is accomplished by means of automatic switches which are set into action upon the initiation of an incoming call, and so far as I am aware these switching mechanisms which are in use at this time require, as a common fea ture, that the line circuit shall be retained in a closed condition. It is because of this requirement that the present type of signaling mechanism which depends upon the breaking of the circuit to despatch the code signal is unserviceable. Briefly stated, my invention consists in bridging the signaling contact by a high resistance element'and providing in conjunction therewith a circuit comprising relatively high and low resistance relays, the former being employed for holding the circuit of the release magnet of the connector switch open during the transmission'of the alarm signal impulses, and the latter (the low resistance relay) operating as a repeater for transmitting the current impulses over the fire alarm circuit.

In the illustration I have shown a fire alarm box mechanism, indicated generally by A, comprising the code wheel A. and a revoluble cam A which parts, it will be understood, are mounted for simultaneous rotation and are adapted to be driven by any suitable mechanism, preferably by a clocktrain, illustration of which has been omitted. During the rotation of the code wheel A the contact point a is vibrated into and out of engagement with the spring 6 when the laterally projecting finger attached to itdrops into the notches between the teeth of the wheel A. The spring Z) normally engages the spring 0 and is held in contact therewith by an insulated pin 0 on a pivoted rock arm A which is released by the movement of the cam member A when the box mechanism is set into operation. The latter also is provided with a set of contacts d and e which are normally separated, the latter being held out of engagement with the former by the stud e on the arm A The telephone subscribers instrument circuit comprises the line wires 1 and 2, the first being connected by the wire 1 to the spring 0, while the second extends beyond the terminals of the box, as indicated by 2 to the central ofiice switches, although within the box mechanism said wire 2 is tied to the contact a by the lead 2. Leading from the wire 2 isthe branch 1 connected to one terminal of the high resistance spool D, of approximately 3500 ohms, the other terminal of which is connected by the wire 6 to the contact spring 6. It will be noted that the contact springs d and b are connected by the wire cl so that the resistance D, which is normally cut out of the circuit will be bridged across the line wires 1 and 2 as soon as the box mechanism begins its cycle of operation.

As previously mentioned, the call distributing mechanism operates to automatically connect one of a large number of lines, for

instance, a group of one hundred subscrib- 'ers" instrument circuits, to one idle trunk of "when actuated by suitable mechanism, such as that disclosed in the Frank Newforth Jr. Patent No. 1,078,690, granted November 18, 1913, are retained in the actuated position by a trunk holding relay employed to prevent the disengagement of the wipers while it is retained in energized condition, but permitting their release when it is deenergized.

This trunk holding relay is indicated by 5 and is shown arranged in the circuit composed of the wires 6 and 7 in which is interposed a battery X and a pair of contacts 8 and 9.

The trunks over which the calls are dis tributed in some instances to the central oflice from outlying stations and in other instances to the different operators stations on the switchboard, comprise the wires 3 and 1 the former terminating in the sleeve contact 3 and the latter ending in the tip contact spring 4P of a switchboard jack with which cooperates the plug of the fire alarm cord circuit comprising a tip 10 and sleeve 11. The trunk circuit is provided with a closed branch containing the high resistance relay 12 which serves to hold the contacts 8 and 9 together to prevent the release of the connector switch. This branch of the trunk comprises the wire i leading from the wire 3 to one terminal of the coil of relay 12, the other extremity of the latter being connected by the wires 71, and h to battery X from which leads the wire 9 to a back contact 7' on the spring 49. From this it will be seen that when the subscribers circuit is closed and the connector switch has picked up the idle trunk it is allowed to remain in this operated position while the subscribers circuit is in operation. The fire alarm cord circuit comprises a low resistance relay 13 which may be connected in multiple with the high resistance 12 and employed to control the contacts 14: and 15 of the outgoing fire alarm circuit, shown as comprising the wires 16 and 17 in which are interposed the battery X and the fire alarm signaling and recording mechanism F. The cord circuit is arranged as follows: The wire it is connected by wire 72, to one terminal of the coil 13, the circuit being completed over the wire j leading to the sleeve contact 11 of the switchboardplug.

The tip contact 10 of said plug is connected to the positive side of the battery X by the wire in which is interposed a windingk.

In describing the operation of the apparatus in detail, it will be understood that when the alarm mechanism is set into operation by the release of the clock train which drives the code wheel A and the cam A simultaneously, the cam wheel first releases the lever A before the first notch in the code wheel relieves the tension on the finger a and the spring a, consequently the latter is engaged by the spring Z). The code wheel A makes a plurality of complete revolutions for every complete revolution of the cam wheel A The closing of the contacts a and b bridges the subscribers telephone set and closes the line with the result that the call distributing switch is actuated to seize an idle trunk, current flowing over the circuit thus established as follows: battery X", wire 9, contact 7, spring 4", wire 1, wiper 4t, wire 1", springs b and a, wires 2 and 2", wiper 3, wires 3*, i, coil of relay 12, wires h, h to battery X The energizing of the relay 12 holds the contacts 8 and 9 of the line switch releasing circuit closed so that the idle trunk seized by the wipers 3 and 4: will be held during the pulsations occurring in the subscribers circuit, due to the transmitting of the fire alarm signal impulses. The rotation of the code wheel A permits the contact spring a to be disengaged from the spring I) each time one of the teeth or notches of the wheel passes the finger a. There is a second bridge on this circuit comprising the wire 1 the high resistance D, wire 6, spring 6, spring (Z, wire d, which is also closed to include in the telephone circuit a high resistance during the opening and closing of the shunt springs a and b. By this time, the plug of the fire alarm cord circuit has been inserted in a subscribers jack and impulses which occur therein are transmitted over the following circuit: battery X resistance k, wire in, tip contact 10, spring 1-, wire 4, wiper 4, wire 1", springs b, a, wires 2, 2", wiper 3, wire 3 sleeve contact spring 3", contact 11, wire j, relay coil 13, wires h 71, to battery X With each variation of the potential of thecurrent in the above circuit occurring upon the separation of the contacts a and b, a corresponding movement of the armature of the low wound relay 13 is efifected to close and open the contacts 1-1- and 15 by means of which the code signal is repeated over the fire alarm circuit and recorded by the apparatus F. The relay 12 is not deenergized by this varying of the potential of the subscribers line circuit as it is of high resistance and delicately adjusted. The relay 13 is of low resistance and does not remain operated when the subscribers telephone line circuit is closed only through the high resistance shunt D. The relay 13, therefore, operates in unison with the making and breaking of the springs a and b,

phone set is connected to the main circuit and by means of which the telephone set is disconnected from said circuit, a high resistance arranged to be thrown into the circuit between the impulses aforesaid, maintaining the circuit energized and closed, and relays, one of said relays being operable during the impulses and the other of said' relays being operative between the impulses.

2. The combination with a circuit, an alarm mechanism connected thereto and ar ranged to send impulses of current thereover, a telephone set connected to said cir cuit, contacts under the control of said alarm mechanism through which the telephone set is connected to the main circuit and by means of which the telephone set'is disconnected from said circuit, a high resistance arranged to be'thrown into thecircuit between the impulses aforesaid, maintaining the circuit energized and closed, an alarm circuit arranged to be connected to said main circuit, and switching mechanism adapted to disconnect said alarm circuit from said main circuit when the latter is opened.

3. The combination with a circuit, an alarm mechanism connected thereto and arranged to send impulses of current-there over, a telephone set connected to said circuit, contacts under the control of said alarm mechanism through which the telephone set is connected to the main circuit and by means of which the telephone set is disconnected from said circuit, a highresistance arranged to be thrown into the circuit between the impulses aforesaid, maintaining the circuit energized and closed, an alarm circuit arranged to be connected to said circuit and two relays, one operable during the impulses to close said alarm circuit, and

' the other operable between impulses and switching mechanism adapted to connect one of a plurality of subscribers lines to another line upon the closing of a subscribers line and also to automatically restore to its normal position upon the opening of the subscribers line, of analarm mechanism on said line adapted to take possession there of and close the same to cause the operation of said switching mechanism, and despatch impulses over the line by opening and closing thesame, and means associated with said alarm mechanism for maintaining the line closed upon the opening thereof by said alarm mechanisl'n.

5. The combination with a subscribers line circuit, of an automatic switching mechanism adapted to connectsaid line circuit to another circuit upon the closing of the line circuit and to restore to its normal position, to disconnect said circuits upon the opening of said line circuit, of an alarm mechanism bridged across said line circuit provided with contacts to close and open said circuit, and a resistance associated with said alarm mechanism for maintaining the line circuit closed when the contacts aforesaid are open.

6. The combination with a' subscribers line circuit, of an automatic switching mechanism adapted to connect said line circuit to another circuit upon the closing thereof and to restore to its normal position upon the opening of said line circuit, a resistance,

and an alarm mechanism arranged to simultaneously bridge said resistance across the circuit and close the latter.

7 The combination with a subscribers line circuit, of an automatic switching mechanism adapted to connect said line circuit to another circuit upon the closing of the former and restore to its normal position upon the opening thereof, a resistance, an alarm mechanism, andnormally open con tacts under the control of the alarm mechanism for bridging said resistance across the line circuit.

8. The combination with a subscribers line circuit, of an automatic switching mechanism adapted to connect said lino circuit to another circuit upon the closing of the former and restore to its normal position upon the opening thereof, a resistance, an alarm mechanism, and normally open contacts under the control of the alarm mechanism for bridging said resistance across'the line circuit to normally close said line circuit during the operation of said alarm mechanis 9. The combination with a subscribers line circuit, of an automatic switching mechanism adapted to connect said line circuit to another circuit upon the closing of the former and restore to its normal position upon the opening thereof, a resistance, an

alarm mechanism, and two sets of contacts under the control of said alarm mechanism for simultaneously bridging the reslstance across the line circuit and closing the. same. 10. The comblnatlon with a subscribers one with each side'of the line circuit, and means under the control of the alarm mechanism'for closing the resistance contacts to bridge the resistance across the line circuit and to close and open the'contacts connected with the line circuit.

V 11. The combination with a subscribers line circuit, of an automatic switching mechanism adapted to connect said line circuit to another circuit upon the closing of the I former and'restore to its normal position upon the opening thereof, a resistance, an alarm mechanism, means under the control of said alarm mechanism for bridging the resistance across the line circuit to maintain said 'circuit closed, and further means likewise under the control of the alarm mechanism vfor short circuiting said resistance.

12. The combination with a subscribers.

line circuit, of an automatic switching mechanlsm adapted to connect said hne clrcuit to another circuit upon the closing of the former and restore to its normal position upon the openmg thereof, a resistance, an

alarm mechanism, means under the control of said alarm mechanism for bridging the resistance across the line c1rcu1t to maintain said circuit closed during the entire operation of said mechanism, and further means 30 likewise under the control of the alarm mech anism'for periodically short circuiting said resistance.

, 13. .The combination with a subscribers' line c1rcu1t, of an ZLHtOIIliLDlOSWltChlHg mechoperation of said mechanism, and further means likewise, under the control of the alarmmechanism for periodically short c1rcuiting said resistance and simultaneously closing the line circuit.

- 14. In an alarm apparatus, the combination with asubscribers circuit, a central ex change and automatic switching mechanism associated with said circuit, of means for rendering said mechanism unresponsive to impulses of current transmitted over said circuit comprising van electromagnet arranged to restrain the action of the switch having a'circuit,-.an alarm circuit provided;

with alarm apparatus, an operating circuit having relatively high and low resistance relays therein, the former arranged to con trol the restraining'magnet circuit and the latter to control the alarm circuit and means for transmitting impulses of current over the subscribers 'clrcult and the connected operatlng c1rcu1t,

15. The combination with, a .subscribers telephone line circuit, a central exchange, an operating circuit adapted to be connected to the subscribers line having relatively high and low resistance relays therein and automatic switching mechanism employed for establishing a portion of the connection existing between the line and operating cir cuits which is normally susceptible to the actionof current impulses on the line, of an electromagnet cooperating with said mechanism to render it unresponsive to such impulses having a circuit which is controlled by the high resistance relay during the action of the low resistance relay, an alarm circuit controlled by the latter and means for producing current impulses on the line.

16. The combination with a subscribers telephone line circuit, a central exchange, a line switch serving to automatically connect the subscribers circuit to a trunk leading to the central exchange which is normally capable of automatically restoring itself to disconnect the line when the latter is opened, and an alarm operating circuit at the central oflice adapted to be connected to the line having relatively high and low resistance relays, of an electro-magnet arranged to restrain the release operation of the switch having a circuit controlled by the high resistance relay, an alarm circuit having alarm mechanism therein arranged to be controlled by the low resistance relay and means for despatching impulses of current over the connected line and alarm operating circuits.

17. The combination with a subscribers telephone line circuit, a central exchange, an alarm operating circuit adapted to be connected to the line circuit having relatively high and low resistance relays therein, and an impulse despatching mechanism arranged to bridge a high resistance across the line circuit and to subsequently open and close the circuit within said bridge, of a switch serving to establish a portion of the connection existing between the line and operating circuits which is susceptible to the action of current impulses on the line, an electromagnet for rendering said switch unresponsive to such impulses having a circuit controlled by the high resistance relay, and an alarm circuit controlled by the low resistance relay, the latter acting to cause current impulses on the line circuit to be repeated on the alarm circuit.

18. The combination with a subscribers line circuit and telephone set, of a resistance, an alarm mechanism, means under the control of the alarm mechanism for cutting the telephone set from the line and simultaneously closing the line circuit, and means also under the control of the alarm mechanism for bridging the resistance across the line circuit.

[19. The combination with a subscribers line circuit and telephone set of a resistance, ance across the line to maintain the same an alarm mechanism, means under the connormally closed during the operation of the 10 trol of the alarm mechanism for cutting the alarm mechanism. telephone set from the line and simultaneously closing the line circuit and to further periodically open and close said line circuit, Witnesses:

and means. also under the control of the HYMAN L. WEIss, alarm mechanism for bridging the resist- B. B. CLARK.

DAVID Gr. DEE.

Gopies of this patent may be obtained for five cents each, by addressing the Commissioner of latents, Washington, D. G. 

